1. Field of the Invention
This invention relates to a semiconductor manufacturing apparatus for mounting an optical semiconductor element on a chip carrier, for example, and more particularly to a semiconductor manufacturing apparatus capable of mounting various types of chip carriers precisely in a preset position on a stage at any time.
2. Description of the Related Art
In general, different types of optical semiconductor elements are sometimes incorporated into an optical communication module. The optical semiconductor elements are separately mounted on chip carriers formed of ceramics, for example, to simplify the incorporation into and the maintenance of the optical communication module.
FIGS. 5 and 6 show conventional semiconductor manufacturing apparatuses. The optical semiconductor element is mounted on the chip carrier by use of the above manufacturing apparatus.
In the conventional semiconductor manufacturing apparatus shown in FIG. 5, a circular stage 1 is formed of metal and can be heated. The surface of the stage 1 has first, second and third surfaces 2, 3 and 4 and stepped portions are formed between the first and second surfaces 2 and 3 and between the second and third surfaces 3 and 4. A rectangular concave portion 6 for positioning a chip carrier 5 is formed in the central portion of the stepped portion between the first and second surfaces 2 and 3. The carrier chip 5 is mounted in the concave portion 6 on the second surface 3. The chip carrier 5 is depressed against the side surface of the concave portion 6 by a depressing plate 7 which is movably disposed on the second surface 3 and fixed in the position. That is, a holding plate 8 disposed on the depressing plate 7 has both ends in the lengthwise direction thereof fixed on the second surface 3 by means of screws 9a and a gap in which the depressing plate 7 can be moved is provided between the holding plate 8 and the second surface 3. The depressing plate 7 is fixed on a clamp portion 10 by means of screws 9b and the clamp portion 10 is disposed to freely move on the third surface 4.
With the above semiconductor manufacturing apparatus, since a chip carrier is disposed inside the rectangular concave portion 6, a chip carrier which is larger than the concave portion 6 cannot be dealt with. If the size of the concave portion 6 is increased, the position of the chip carrier in the concave portion 6 cannot be precisely determined, lowering the positioning precision of an optical semiconductor element to be mounted on the chip carrier.
Further, with the conventional semiconductor manufacturing apparatus shown in FIG. 6, the chip carrier 5 is mounted on the circular plate-like metal stage 11 which can be heated, a semi-circular depressing plate 12 is mounted on one end portion of the chip carrier 5, and the chip carrier 5 is depressed against the stage 11 by means of the depressing plate 12 and fixed there.
A chip carrier is extremely small and is generally several mm square. Therefore, as shown in FIG. 6, when one end portion of the chip carrier 5 is depressed by the depressing plate 12, the other end portion of the chip carrier is lifted from the stage 11 and the chip carrier cannot be fixedly positioned. Further, when the chip carrier 5 is depressed by means of the depressing plate 12, a metal film such as an electrode which covers the surface of the chip carrier 5 may be sometimes damaged.